1. Field of the Invention
This invention relates to a fan, particularly to a design of the shape of a fan and fan blades.
2. Description of the Prior Art
FIG. 1 shows the shape of a conventional fan. The conventional fan 1 comprises a center portion 11 and a plurality of fan blades 12. According to the rotational direction F, the outermost point 1211 of the front side 121 of fan blade 12 is equal in height to the innermost point 1212 of the front side 121. According to the rotational direction F, the front side 121 is a portion first contacting air. Because the whole face of the front side 121 first contacts air, the noise created by the conventional fan is very high. Furthermore, the wake side 122 is a plane surface such that the air contacting the fan blade can drain away from the wake side 122, and a turbulence is easily created to reduce the air flow and the wind pressure. It is necessary to provide a fan with low noise, high air flow and high wind pressure.